Study of the Effect of Oiliness Agents in the Presence of Detergents on Friction Characteristics of Paper-Based Friction Materials Under Low Sliding Velocity

摘要

In this paper the mechanism of friction reduction of paper-based friction materials was studied when both oiliness agent and metallic detergent were used together. When oleic acid and overbase calcium sulfonate were mixed together, the friction coefficient in the low sliding velocity range was lower than that obtained when either oleic acid or overbase calcium sulfonate was used alone. In contrast, when oleylamine and overbase calcium sulfonate were mixed together, the friction coefficient was intermediate between the friction levels obtained when the two additives were used separately. This result shows that the friction reduction ability of oleylamine is inhibited by the overbase calcium sulfonate. The reason for this result is as follows. First, when both overbase calcium sulfonate and oleic acid were mixed, the friction coefficient decreased because the calcium carbonate film increased the adsorption strength of the oleic acid. In contrast, when overbase calcium sulfonate and oleylamine were both mixed, the presence of the calcium carbonate film inhibited the adsorption of the oleylamine. In addition, the friction coefficient of oleylamine is higher than that of oil alone even in the presence of neutral calcium sulfonate. So the adsorption of the oleylamine is also inhibited in the presence of the calcium sulfonate soap, resulting in weaker friction reduction for the oleylamine.